Evidence for genetic heterogeneity between clinical subtypes of bipolar disorder.

We performed a genome-wide association study of 6447 bipolar disorder (BD) cases and 12 639 controls from the International Cohort Collection for Bipolar Disorder (ICCBD). Meta-analysis was performed with prior results from the Psychiatric Genomics Consortium Bipolar Disorder Working Group for a combined sample of 13 902 cases and 19 279 controls. We identified eight genome-wide significant, associated regions, including a novel associated region on chromosome 10 (rs10884920; P=3.28 × 10-8) that includes the brain-enriched cytoskeleton protein adducin 3 (ADD3), a non-coding RNA, and a neuropeptide-specific aminopeptidase P (XPNPEP1). Our large sample size allowed us to test the heritability and genetic correlation of BD subtypes and investigate their genetic overlap with schizophrenia and major depressive disorder. We found a significant difference in heritability of the two most common forms of BD (BD I SNP-h2=0.35; BD II SNP-h2=0.25; P=0.02). The genetic correlation between BD I and BD II was 0.78, whereas the genetic correlation was 0.97 when BD cohorts containing both types were compared. In addition, we demonstrated a significantly greater load of polygenic risk alleles for schizophrenia and BD in patients with BD I compared with patients with BD II, and a greater load of schizophrenia risk alleles in patients with the bipolar type of schizoaffective disorder compared with patients with either BD I or BD II. These results point to a partial difference in the genetic architecture of BD subtypes as currently defined.

Genetic investigation of chromosome 5q GABAA receptor subunit genes in schizophrenia.

We previously performed a genome-wide linkage scan in Portuguese schizophrenia families that identified a risk locus on chromosome 5q31-q35. This finding was supported by meta-analysis of 20 other schizophrenia genome-wide scans that identified 5q23.2-q34 as the second most compelling susceptibility locus in the genome. In the present report, we took a two-stage candidate gene association approach to investigate a group of gamma-aminobutyric acid (GABA) A receptor subunit genes (GABRA1, GABRA6, GABRB2, GABRG2, and GABRP) within our linkage peak. These genes are plausible candidates based on prior evidence for GABA system involvement in schizophrenia. In the first stage, associations were detected in a Portuguese patient sample with single nucleotide polymorphisms (SNPs) and haplotypes in GABRA1 (P=0.00062-0.048), GABRP (P=0.0024-0.042), and GABRA6 (P=0.0065-0.0088). The GABRA1 and GABRP findings were replicated in the second stage in an independent German family-based sample (P=0.0015-0.043). Supportive evidence for association was also obtained for a previously reported GABRB2 risk haplotype. Exploratory analyses of the effects of associated GABRA1 haplotypes on transcript levels found altered expression of GABRA6 and coexpressed genes of GABRA1 and GABRB2. Comparison of transcript levels in schizophrenia patients and unaffected siblings found lower patient expression of GABRA6 and coexpressed genes of GABRA1. Interestingly, the GABRA1 coexpressed genes include synaptic and vesicle-associated genes previously found altered in schizophrenia prefrontal cortex. Taken together, these results support the involvement of the chromosome 5q GABAA receptor gene cluster in schizophrenia, and suggest that schizophrenia-associated haplotypes may alter expression of GABA-related genes.

Support for involvement of neuregulin 1 in schizophrenia pathophysiology.

Schizophrenia is a common, multigenic psychiatric disorder. Linkage studies, including a recent meta-analysis of genome scans, have repeatedly implicated chromosome 8p12-p23.1 in schizophrenia susceptibility. More recently, significant association with a candidate gene on 8p12, neuregulin 1 (NRG1), has been reported in several European and Chinese samples. We investigated NRG1 for association in schizophrenia patients of Portuguese descent to determine whether this gene is a risk factor in this population. We tested NRG1 markers and haplotypes for association in 111 parent-proband trios, 321 unrelated cases, and 242 control individuals. Associations were found with a haplotype that overlaps the risk haplotype originally reported in the Icelandic population ("Hap(ICE)"), and two haplotypes located in the 3' end of NRG1 (all P<0.05). However, association was not detected with Hap(ICE) itself. Comparison of NRG1 transcript expression in peripheral leukocytes from schizophrenia patients and unaffected siblings identified 3.8-fold higher levels of the SMDF variant in patients (P=0.039). Significant positive correlations (P<0.001) were found between SMDF and HRG-beta 2 expression and between HRG-gamma and ndf43 expression, suggesting common transcriptional regulation of NRG1 variants. In summary, our results suggest that haplotypes across NRG1 and multiple NRG1 variants are involved in schizophrenia.

Genome-wide scan in Portuguese Island families implicates multiple loci in bipolar disorder: fine mapping adds support on chromosomes 6 and 11.

As part of an extensive study in the Portuguese Island population of families with multiple patients suffering from bipolar disorder and schizophrenia, we performed an initial genome-wide scan of 16 extended families with bipolar disorder that identified three regions on chromosomes 2, 11, and 19 with genome-wide suggestive linkage and several other regions, including chromosome 6q, also approached suggestive levels of significance. Dick et al. [2003: Am J Hum Genet 73:107-114] recently reported in a study of 250 families with bipolar disorder a maxLOD score of 3.61 near marker D6S1021 on chromosome 6q. This study replicates this finding having detected a peak NPL = 2.02 (P = 0.025) with the same marker D6S1021(104.7 Mb). Higher-density mapping provided additional support for loci on chromosome 6 including marker D6S1021 with an NPL = 2.59 (P = 0.0068) and peaking at marker D6S1639 (125 Mb) with an NPL = 3.06 (P = 0.0019). A similar pattern was detected with higher-density mapping of chromosome 11 with an NPL = 3.15 (P = 0.0014) at marker D11S1883 (63.1 Mb). Simulations at the density of our fine mapping data indicate that less than 1 scan out of 10 would find two such scores genome-wide in the same scan by chance. Our findings provide additional support for a susceptibility locus for bipolar disorder on 6q, as well as, suggesting the importance of denser scans. Published 2004 Wiley-Liss, Inc.

Genomewide linkage analysis of bipolar disorder by use of a high-density single-nucleotide-polymorphism (SNP) genotyping assay: a comparison with microsatellite marker assays and finding of significant linkage to chromosome 6q22.

We performed a linkage analysis on 25 extended multiplex Portuguese families segregating for bipolar disorder, by use of a high-density single-nucleotide-polymorphism (SNP) genotyping assay, the GeneChip Human Mapping 10K Array (HMA10K). Of these families, 12 were used for a direct comparison of the HMA10K with the traditional 10-cM microsatellite marker set and the more dense 4-cM marker set. This comparative analysis indicated the presence of significant linkage peaks in the SNP assay in chromosomal regions characterized by poor coverage and low information content on the microsatellite assays. The HMA10K provided consistently high information and enhanced coverage throughout these regions. Across the entire genome, the HMA10K had an average information content of 0.842 with 0.21-Mb intermarker spacing. In the 12-family set, the HMA10K-based analysis detected two chromosomal regions with genomewide significant linkage on chromosomes 6q22 and 11p11; both regions had failed to meet this strict threshold with the microsatellite assays. The full 25-family collection further strengthened the findings on chromosome 6q22, achieving genomewide significance with a maximum nonparametric linkage (NPL) score of 4.20 and a maximum LOD score of 3.56 at position 125.8 Mb. In addition to this highly significant finding, several other regions of suggestive linkage have also been identified in the 25-family data set, including two regions on chromosome 2 (57 Mb, NPL = 2.98; 145 Mb, NPL = 3.09), as well as regions on chromosomes 4 (91 Mb, NPL = 2.97), 16 (20 Mb, NPL = 2.89), and 20 (60 Mb, NPL = 2.99). We conclude that at least some of the linkage peaks we have identified may have been largely undetected in previous whole-genome scans for bipolar disorder because of insufficient coverage or information content, particularly on chromosomes 6q22 and 11p11.

Genome-wide scan in Portuguese Island families identifies 5q31-5q35 as a susceptibility locus for schizophrenia and psychosis.

Schizophrenia is a common psychiatric disorder with a complex genetic etiology. To understand the genetic basis of this syndrome in Portuguese Island populations, we performed a genome-wide scan of 29 families with schizophrenia, which identified a single region on 5q31-5q35 with strong linkage (NPL=3.09, P=0.0012 at D5S820). Empirical simulations set a genome-wide threshold of NPL=3.10 for significant linkage. Additional support for this locus in schizophrenia comes from higher-density mapping and mapping of 11 additional families. The combined set of 40 families had a peak NPL=3.28 (P=0.00066) at markers D5S2112-D5S820. These data and previous linkage findings from other investigators provide strong and consistent evidence for this genomic region as a susceptibility locus for schizophrenia. Exploratory analyses of a novel phenotype, psychosis, in families with schizophrenia and bipolar disorder detected evidence for linkage to the same markers as found in schizophrenia (peak NPL=3.03, P=0.0012 at D5S820), suggesting that this locus may be responsible for the psychotic symptoms observed in both diseases. Molecular Psychiatry (2004) 9, 213-218. doi:10.1038/sj.mp.4001418 Published online 30 December 2003

Marketing to America's youth: evidence from corporate documents.

OBJECTIVE: To evaluate the claim that the tobacco industry does not market its products to youth. DESIGN: The data for this study come from tobacco industry documents collected from the tobacco industry's document websites, presently linked at http://www.tobaccoarchives.com. The websites were searched using "request for production" (RFP) codes, specified keyword searches, and serendipitous terms identified in document citations found with RFP and keyword searches. RESULTS: Industry documents show that the cigarette manufacturers carefully monitored the smoking habits of teenagers over the past several decades. Candid quotes from industry executives refer to youth as a source of sales and as fundamental to the survival of the tobacco industry. The documents reveal that the features of cigarette brands (that is, use of filters, low tar, bland taste, etc), packaging (that is, size, colour and design), and advertising (that is, media placements and themes and imagery) were developed specifically to appeal to new smokers (that is, teenagers). Evidence also indicates that relevant youth oriented marketing documents may have been destroyed and that the language used in some of the more recent documents may have been sanitised to cover up efforts to market to youth. CONCLUSIONS: The tobacco industry's internal documents reveal an undeniable interest in marketing cigarettes to underage smokers. The industry's marketing approaches run counter to and predicate methods for tobacco prevention: (1) keep the price of the product high; (2) keep product placements and advertising away from schools and other areas with a high volume of youth traffic; (3) make cigarette advertising (that is, themes and visual images) unappealing to youth; (4) make product packaging unappealing to youth; and (5) design the product so it is not easy to inhale.

Tax, price and cigarette smoking: evidence from the tobacco documents and implications for tobacco company marketing strategies.

OBJECTIVE: To examine tobacco company documents to determine what the companies knew about the impact of cigarette prices on smoking among youth, young adults, and adults, and to evaluate how this understanding affected their pricing and price related marketing strategies. METHODS: Data for this study come from tobacco industry documents contained in the Youth and Marketing database created by the Roswell Park Cancer Institute and available through http:// roswell.tobaccodocuments.org, supplemented with documents obtained from http://www.tobaccodocuments.org. RESULTS: Tobacco company documents provide clear evidence on the impact of cigarette prices on cigarette smoking, describing how tax related and other price increases lead to significant reductions in smoking, particularly among young persons. This information was very important in developing the industry's pricing strategies, including the development of lower price branded generics and the pass through of cigarette excise tax increases, and in developing a variety of price related marketing efforts, including multi-pack discounts, couponing, and others. CONCLUSIONS: Pricing and price related promotions are among the most important marketing tools employed by tobacco companies. Future tobacco control efforts that aim to raise prices and limit price related marketing efforts are likely to be important in achieving reductions in tobacco use and the public health toll caused by tobacco.

Tobacco Institute lobbying at the state and local levels of government in the 1990s.

OBJECTIVE: To describe variation in Tobacco Institute (TI) lobbying expenditures across states and test whether these expenditures vary in relationship to measures of tobacco control activity at the state level. INDEPENDENT VARIABLE: Data for this study came from the TI's State Activities Division (SAD) annual budgets for the years 1991-97, excluding 1993. These data include budgetary information pertaining to state and local lobbying activity and special projects reported by state. DEPENDENT VARIABLES: The following measures of state tobacco control activity during the period 1991 to 1997 were considered: (1) American Stop Smoking Intervention Study (ASSIST) funding; (2) voter initiatives to raise cigarette taxes; (3) cigarette excise tax level; (4) workplace smoking restrictions; (5) the intensification of smoke-free air laws covering private worksites, government worksites, and restaurants; (6) the intensification of strength of sales to minors laws; (7) the intensification of strength of laws that punish minors for possessing, purchasing, and/or using cigarettes; (8) state status as a major grower of tobacco; (9) partisan control of state government, 1996; and (10) an overall composite index reflecting a state's strength of tobacco control, combining cigarette prices with workplace and home smoking bans. RESULTS: The overall annual budget for the TI declined steadily during the 1990s, from $47.7 million in 1991 to $28.1 million by 1996. The proportion of the TI's budget allocated to the SAD remained relatively stable at about 30%. TI expenditures for lobbyists were highest in California where tobacco control activity has been strong for the past decade. We found significant associations between TI SAD expenditures and cigarette excise tax levels, the status of a state as a recipient of federal ASSIST funds, and changes in the strength of statewide laws that penalise minors for possessing, purchasing, and/or using cigarettes. We found little or no association between state and local lobbying budgets of the TI and changes in statewide smoke-free air laws, although we did find evidence of TI special project expenditures earmarked to specific states and localities to resist clean indoor air legislation/regulations (that is, Maryland and New York City). We found no significant correlation between TI lobbying expenditures and sales to minors' laws, status as a major producer of tobacco, or partisan control of state government. CONCLUSIONS: The findings from this study support the hypothesis that in the 1990s tobacco control activities such as raising cigarette excise taxes and participation in ASSIST attracted TI resources to undermine these efforts.

Failed promises of the cigarette industry and its effect on consumer misperceptions about the health risks of smoking.

BACKGROUND: In January 1954, US tobacco manufacturers jointly sponsored an advocacy advertisement entitled "A Frank Statement to Cigarette Smokers" which appeared in 448 newspapers in 258 cities reaching an estimated 43 245 000 Americans. The advertisement questioned research findings implicating smoking as a cause of cancer, promised consumers that their cigarettes were safe, and pledged to support impartial research to investigate allegations that smoking was harmful to human health. OBJECTIVE: To examine (1) the extent to which cigarette companies fulfilled the promises made to consumers in the 1954 "Frank Statement", and (2) the effect of these promises on consumer knowledge, beliefs, and smoking practices. METHODS: This study reviews statements made since 1954 by the tobacco companies individually and collectively through the Tobacco Institute and Tobacco Industry Research Committee/Council for Tobacco Research on the subject of smoking as a cause disease, and the industry's pledge to support and disclose the results of impartial research on smoking and health. Many of the industry documents evaluated in this study were obtained from a collection consisting of 116 documents entitled the "Statement of Defendants' Misrepresentations" prepared by attorneys representing the state of Connecticut in the Medicaid litigation against the tobacco industry in 1998. In addition, we searched for corroborating material from tobacco industry documents collected from the tobacco industry's document websites. In order to contrast industry statements on smoking and health with what smokers' actually believed about smoking we reviewed reports of public polling data on smokers' knowledge and beliefs about smoking and disease gathered from tobacco industry sources and from surveys conducted by public health researchers. RESULTS: Analysis of public statements issued by the tobacco industry sources over the past five decades shows that the companies maintained the stance that smoking had not been proven to be injurious to health through 1999. The public statements of the tobacco industry are in sharp contrast to the private views expressed by many of their own scientists. The tobacco documents reveal that many scientists within the tobacco industry acknowledged as early as the 1950s that cigarette smoking was unsafe. The sincerity of the industry's promise to support research to find out if smoking was harmful to health and to disclose information about the health effects of smoking can also be questioned based upon the industry's own documents which reveal: (1) scepticism about the scientific value of the smoking and health research program established by the industry; and (2) evidence that research findings implicating smoking as a health problem were often not published or disclosed outside the industry. Industry documents also show that the companies knew that their own customers were misinformed about smoking and health issues. CONCLUSION: It is clear that the cigarette companies failed to fulfill the promises made to consumers in the 1954 "Frank Statement" advertisement. The failure of cigarette manufacturers to honour these promises has resulted in a public that even today remains misinformed about the health risks of smoking.